Patient-related factors influencing the effectiveness and safety of Janus Kinase inhibitors in rheumatoid arthritis: a real-world study

In real-world scenarios, Janus Kinase (JAK) inhibitors are often offered to "difficult-to-treat" rheumatoid arthritis patients, quite different from those included in randomized controlled trials. Our study aimed to evaluate the influence of patient-related factors on the effectiveness and safety of JAK inhibitors in real-world clinical practice. This observational retrospective study involved rheumatoid arthritis patients who received treatment with either tofacitinib, baricitinib, upadacitinib, or filgotinib. At 12 months of treatment, reasons for and rates of JAK inhibitor treatment discontinuation were examined. Treatment retentions were analyzed through Cox proportional hazard regression models and Kaplan–Meier estimates. Patient-related factors that could influence treatment retention were evaluated for the discontinuation reasons of lack of effectiveness and adverse events. At 12 months of treatment, discontinuation rates for 189 JAK inhibitor treatments were: lack of effectiveness (24.3%), adverse events (20.6%), and other reasons (3.7%). The remaining 51.4% represents the treatment continuation rate. No patient-related factors evaluated had an influence on treatment discontinuation due to lack of effectiveness. Ae significantly increased the risk of treatment discontinuation due to adverse events (p = 0.030). In terms of age, at 12 month of treatment, discontinuation rates due to adverse events were: